Do you remember when Superman crushed a piece of coal with his hands and turned it into a diamond?
There were two issues that people were quick to point out at the time.
First, the diamond was perfectly formed.
Second, Superman did not use his heat ray in the process of making the diamond. And the heat, around 1900 degrees Celsius, was considered necessary to make diamonds in the lab – until now.
Researchers at Australian National University and RMIT University created diamonds in “minutes, without heat – mimicking the force of an asteroid collision.”
Natural diamonds typically form over billions of years, about 150 kilometers deep in the Earth, where pressures and temperatures are high above 1,000 degrees.
One of the principal investigators is Professor Jodie Bradby of Electronic Materials Engineering at ANU’s School of Physics Research. She said the breakthrough “shows that Superman may have had a similar trick up his sleeve.”
An international team, led by Australian universities, made two types of diamonds: “The type found on an engagement ring and another type of diamond called Lonsdaleite, which is found in nature at the site of meteorite impacts such as than Canyon Diablo in the United States. . “
Lonsdaleite, named after crystallographer Dame Kathleen Lonsdale, the first woman elected to the Royal Society, has a different crystal structure than ordinary diamond.
It is predicted to be 58% harder – and is “considered the hardest natural material on Earth.”
Tiny amounts of Lonsdaleite have been synthesized in laboratories by heating and compressing graphite, using a high-pressure press or explosives, according to a statement from the researchers.
“Lonsdaleite has the potential to be used to cut ultra-strong materials at mine sites,” said Professor Bradby.
“Creating more of this rare but super useful diamond is the long term goal of this work.”
In what is described as an “unexpected discovery,” Lonsdaleite and regular diamond were formed at normal room temperatures by simply applying high pressure – “equivalent to 640 African elephants on the tip of a ballet shoe. “.
Professor Bradby said the discovery was made by changing the way pressure is applied.
“The twist of the story is how we apply pressure. In addition to very high pressures, we also allow the carbon to undergo something called “shear” – which is like a twisting or sliding force. We believe this allows carbon atoms to fall into place and form Lonsdaleite and regular diamond. “
RMIT Co-Principal Investigator Professor Dougal McCulloch used new advanced electron microscopy techniques to capture solid and intact slices from experimental samples to create snapshots of the formation of the two types of diamonds.
“Our photos have shown that ordinary diamonds only form in the middle of these Lonsdaleite veins,” said Professor McCulloch.
“Seeing these little rivers of Lonsdaleite and regular diamond for the first time was just amazing and really helps us understand how they might form.”
As the researchers explain in an article at The conversation, diamonds have been synthesized in laboratories since 1954.
Then General Electric’s Howard Tracy Hall created them using a process that mimicked the natural conditions of the earth’s crust, adding metal catalysts to speed up the growth process.
The result was high pressure, high temperature diamonds similar to those found in nature, but often smaller and less perfect. These are still manufactured today, mainly for industrial applications.
“Nature has provided clues to other ways of forming diamonds, including during the violent impact of meteorites on Earth, as well as in processes such as high speed asteroid collisions in our solar system – creating what we call ‘alien diamonds’, ”the researchers write.
The team, which included the University of Sydney and the Oak Ridge National Laboratory in the United States, published the research results in the journal Small.